Troubleshoot

Problem:

install: can't change permissions of /usr/local/bin: Operation not permitted
"Unable to remove symlink. You must have SUDO privileges"
"Unable to create symlink. You must have SUDO privileges"
install: cannot create regular file '/usr/local/bin/testtfswitch': Permission denied

Solution: You probably need to have privileges to install testtfswitch at /usr/local/bin.

Try the following.

wget https://raw.githubusercontent.com/warrensbox/terraform-switcher/release/install.sh 
chmod 755 install.sh
./install.sh -b bin-directory

./bin-directory/testtfswitch
wget https://raw.githubusercontent.com/warrensbox/terraform-switcher/release/install.sh 
chmod 755 install.sh
./install.sh -b bin-directory

./bin-directory/testtfswitch

Or, use the custom directory option -b:
drawing

https://camo.githubusercontent.com/dad8aa8e1b2028f5cf35a83c0b58d9a47c591627/68747470733a2f2f73332e75732d656173742d322e616d617a6f6e6177732e636f6d2f6b65706c65722d696d616765732f77617272656e73626f782f74667377697463682f74667377697463682e676966